Evaluation of the Efficacy and Tolerance of Low Doses of Ethosuximide in the Treatment of Peripheral Neuropathic Pain

Inclusion Criteria:

• Male or female (under effective contraception: pill, implant, IUD, sterilization) aged 18 years or older, suffering from peripheral neuropathic pain (DN4 ≥ 4) for more than 3 months, of intensity ≥ 4 on a numerical scale from 0 to 10, and whose analgesictreatment has been stable for more than a month,
• Patients affiliated to the French Social Security system,
• Patients whose free and informed consent has been obtained.

Exclusion Criteria:

• Pregnancy (βHCG+ blood) or breastfeeding,
• Neuropathic pain due to spinal cord or brain injury, phantom limb pain oralgohallucinosis,
• Fibromyalgia or algodystrophy,
• Chronic pain syndrome that the patient cannot distinguish and/or is more intense thanperipheral neuropathic pain,
• Significant abnormalities in liver (transaminases > 3N, cholestasis) and renal (MDRD < 60 mL/min) tests,
• Ongoing comorbidities: cancer, neurodegenerative pathology
• Severe depressive disorder in progress (as determined by the clinician), history ofsuicide attempts or hospitalization for depression,
• Diabetic patients (contraindicated due to the high sugar concentration ofethosuximide, 3g / 5 ml),
• Patients who have previously received ethosuximide (epilepsy or clinical trial),
• Surgery planned throughout the entire trial,
• Medical and surgical history incompatible with the study,
• Dependence on alcohol and/or drugs (for compliance purposes),
• Known allergy to succinimides (ethosuximide, methsuximide, phensuximide),
• Psychotic disorders,
• Epileptic patients,
• Patients benefiting from a legal protection measure (curatorship, guardianship,deprived of liberty or subject to judicial safeguard).